KR101728827B1

KR101728827B1 - Non-oriented electrical steel sheet and method for manufacturing the same

Info

Publication number: KR101728827B1
Application number: KR1020150186233A
Authority: KR
Inventors: 안영현
Original assignee: 주식회사 포스코
Priority date: 2015-12-24
Filing date: 2015-12-24
Publication date: 2017-04-20

Abstract

The non-oriented electrical steel sheet according to an embodiment of the present invention may contain 0.005% or less (excluding 0%) of C, 1 to 4% of Si, 0.1 to 1% of Mn, 0.01 to 0.1% of P, 0.001 to 0.005% of S, 0.1 to 0.6% of Al, 0.005% or less of N (excluding 0%), 0.005% or less of Ti (excluding 0%), Sn and Sb, , The balance being Fe and unavoidable impurities, satisfying the following formulas 1 to 3, and having an average grain size of 30 to 150 占 퐉.
[Formula 1]
0.05? [P] + [Sn] + [Sb]? 0.15
[Formula 2]
0.5? [P] / ([Sn] + [Sb])? 2
[Formula 3]
(V _{111} + V _{112} ) / ([maximum intensity value]) * 100? 30
(P, Sn and Sb in the formulas 1 to 3 represent the content (% by weight) of P, Sn and Sb, respectively,
V _{111} and V _{112} are the texture fractions of {111} and {112} in the azimuth distribution function image (ODF image, φ2 = 45 degree section) , And [Maximum intensity value] represents the maximum intensity value in the orientation distribution function image (ODF image, φ2 = 45 degree section).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a non-oriented electrical steel sheet,

A non-oriented electrical steel sheet and a manufacturing method thereof.

The nonoriented electrical steel sheet is an important material used as an iron core material in rotating equipment such as motors and generators. Motors and generators transform electrical energy into mechanical energy or mechanical energy into electrical energy. The magnetic properties of the electrical steel sheet used as the main material are very important factors in determining energy efficiency. The typical magnetic properties of the nonoriented electric steel sheet include iron loss and magnetic flux density. The lower the iron loss, the lower the energy loss, and the higher the magnetic flux density, the more the magnetic field can be induced with the same energy. In order to obtain the magnetic flux density, a small current may be applied, so that the magnetic flux density can be reduced, and the higher the magnetic flux density, the better.

Iron loss can be effectively reduced by increasing the amount of Si, Al, Mn, and the like which are the main alloying elements added to the non-oriented electrical steel sheet. Si, Al, and Mn are alloying elements with a high resistivity. Therefore, they are added because they have a large effect of improving iron loss when added. However, since the saturation flux density is decreased, a decrease in magnetic flux density can not be avoided. And the magnetic flux density is also low.

Therefore, in order to develop a non-oriented electrical steel sheet with high magnetic flux density and high magnetic flux density, it is possible to improve the magnetic properties by improving the texture by utilizing special additive elements such as REM, or to perform additional manufacturing processes such as annealing twice And the like. However, all of these technologies cause a rise in manufacturing costs and a decrease in productivity, which leads to difficulties in mass production. Therefore, a technology capable of improving the magnetic properties without increasing the manufacturing cost greatly is necessary.

As a method for developing a non-oriented electrical steel sheet having a high magnetic flux density, hot rolling is carried out at a temperature of A3 or higher. When cooling after hot rolling, the cooling rate from A3 temperature to 200 ° C is 50 ° C / s for better magnetic properties, s, annealing the hot - rolled sheet, cold rolling and annealing the cold - rolled sheet. In order to control the proposed cooling rate, additional equipment is required, which causes a cost increase.

Further, in order to improve the magnetic properties by improving the texture, the composition weight ratio (MnO / SiO ₂ ) of MnO and SiO ₂ in the oxide inclusions in the steel is controlled, and the finish rolling during hot rolling is performed under a condition that the friction coefficient between steel and roll is 0.2 A method of annealing a hot-rolled sheet, annealing a cold-rolled sheet, and annealing a cold-rolled sheet after a finishing rolling temperature of 700 ° C or more is proposed. In this case, since the hot-rolled sheet must be controlled to a thickness of 1.0 mm or less, .

In addition, a process of skin pass rolling and re-annealing at a reduction rate of 3 to 10% in addition to the steps of hot rolling, hot rolling annealing, cold rolling and cold rolling annealing was proposed. This also has the problem of cost increase due to the additional process.

Further, although the method of annealing twice twice including intermediate annealing as a hot-rolled sheet has been proposed, the productivity is lowered and the manufacturing cost is increased. Likewise, a method of adding Sn and rolling twice including intermediate annealing during cold rolling has been proposed, which also has a disadvantage in that the manufacturing cost is increased.
BACKGROUND ART 1: Japanese Laid-Open Patent Publication No. 10-2014-0133681
BACKGROUND ART 2: JP-A-2005-240095

One embodiment of the present invention is to provide a non-oriented electrical steel sheet having excellent magnetic properties and high productivity at the same time by precisely controlling the contents of Si, Mn, Al, P, Sn and Sb in the steel additive components.

Another embodiment of the present invention is to provide a method for manufacturing a non-oriented electrical steel sheet.

The non-oriented electrical steel sheet according to an embodiment of the present invention may contain 0.005% or less (excluding 0%) of C, 1 to 4% of Si, 0.1 to 1% of Mn, 0.01 to 0.1% of P, 0.001 to 0.005% of S, 0.1 to 0.6% of Al, 0.005% or less of N (excluding 0%), 0.005% or less of Ti (excluding 0%), Sn and Sb, , The balance being Fe and unavoidable impurities, satisfying the following formulas 1 to 3, and having an average grain size of 30 to 150 占 퐉.

[Formula 1]

0.05? [P] + [Sn] + [Sb]? 0.15

[Formula 2]

0.5? [P] / ([Sn] + [Sb])? 2

[Formula 3]

(V _{111} + V _{112} ) / ([maximum intensity value]) * 100? 30

(P, Sn and Sb in the formulas 1 to 3 represent the content (% by weight) of P, Sn and Sb, respectively,

V _{111} and V _{112} are the texture fractions of {111} and {112} in the azimuth distribution function image (ODF image, φ2 = 45 degree section) , And [Maximum intensity value] represents the maximum intensity value in the orientation distribution function image (ODF image, φ2 = 45 degree section).

B1 / B50 > = 0.45.

(B1 and B50 represent the value of the magnetic flux density induced in the steel sheet when a current of 100 A / m and 5000 A / m is applied, respectively).

Cu, Ni and Cr in an amount of 0.05 wt% or less (excluding 0 wt%), respectively.

Zr, Mo, and V in an amount of 0.01 wt% or less (excluding 0 wt%), respectively.

A method for manufacturing a non-oriented electrical steel sheet according to an embodiment of the present invention includes: 0.005% or less (excluding 0%) of C, 1 to 4% of Si, 0.1 to 1% of Mn, 0.01 to 1% of P (Excluding 0%), Ti: 0.005% or less (excluding 0%), Sn and Sb are each independently added in an amount of 0.1 to 0.1%, S to 0.001 to 0.005%, Al to 0.1 to 0.6% Or a total of 0.02 to 0.2%, the balance being Fe and inevitable impurities, and heating the slab satisfying the following equations (1) and (2), followed by hot rolling to produce a hot rolled steel sheet; Cold-rolling the hot-rolled sheet to produce a cold-rolled sheet; And a cold-rolled sheet to 900 to include a recrystallization annealing step of a 1100 ℃ and recrystallization in the step of annealing, the annealing of the exit side tension of 0.5 to 1.5kg / mm ^2.

[Formula 1]

0.05? [P] + [Sn] + [Sb]? 0.15

[Formula 2]

0.5? [P] / ([Sn] + [Sb])? 2

(Where P, Sn and Sb in the formulas 1 and 2 represent the contents (% by weight) of P, Sn and Sb, respectively).

In the step of producing the hot rolled sheet, the slab is heated to 1100 to 1250 캜

After the step of producing the hot-rolled sheet, the step of winding the hot-rolled sheet at 500 to 750 占 폚 may be further included.

After the winding step, it may further include annealing the hot-rolled sheet at 900 to 1150 占 폚.

In the step of producing the cold-rolled sheet, the reduction ratio may be 50 to 95%.

The produced steel sheet can satisfy the following formula (3).

[Formula 3]

(V _{111} + V _{112} ) / ([maximum intensity value]) * 100? 30

(Where V _{111} and V _{112} in Equation 3 are _{111} and _{{111} in the} texture analysis of the 3 / 4t portion of the plate thickness, 112}, and [maximum intensity value] represents the maximum intensity value in the orientation distribution function image (ODF image, φ2 = 45 degree section).

The manufactured steel sheet may have a B1 / B50? 0.45.

The prepared steel sheet may have an average grain size of 30 to 150 mu m.

The slab may further contain 0.05 wt% or less (excluding 0 wt%) of Cu, Ni and Cr, respectively.

The slab may further contain Zr, Mo and V in an amount of 0.01 wt% or less (excluding 0 wt%), respectively.

The non-oriented electrical steel sheet according to an embodiment of the present invention has excellent magnetic characteristics and excellent productivity.

The terms first, second and third, etc. are used to describe various portions, components, regions, layers and / or sections, but are not limited thereto. These terms are only used to distinguish any moiety, element, region, layer or section from another moiety, moiety, region, layer or section. Thus, a first portion, component, region, layer or section described below may be referred to as a second portion, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified and that the presence or absence of other features, regions, integers, steps, operations, elements, and / It does not exclude addition.

When referring to a portion as being "on" or "on" another portion, it may be directly on or over another portion, or may involve another portion therebetween. In contrast, when referring to a part being "directly above" another part, no other part is interposed therebetween.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Unless otherwise stated,% means% by weight, and 1 ppm is 0.0001% by weight.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

The non-oriented electrical steel sheet according to an embodiment of the present invention may contain 0.005% or less (excluding 0%) of C, 1 to 4% of Si, 0.1 to 1% of Mn, 0.01 to 0.1% of P, 0.001 to 0.005% of S, 0.1 to 0.6% of Al, 0.005% or less of N (excluding 0%), 0.005% or less of Ti (excluding 0%), Sn and Sb, 0.02 to 0.2%, and the remainder includes Fe and unavoidable impurities.

First, the reason for limiting the components of the non-oriented electrical steel sheet will be described.

C: 0.005 wt% or less

Carbon (C) is combined with Ti to form carbide to dislocate magnetism. It increases to 0.005 wt% or less because it increases iron loss by magnetic aging when used as an electrical product in the final product.

Si: 1 to 4 wt%

Silicon (Si) is a major element added to increase the resistivity of steel and to reduce vortex loss during iron loss. It is added by 1 wt% or more to obtain low iron loss characteristics. On the other hand, since the magnetic flux density decreases as the added amount increases, the magnetic flux density decreases with an increase in the amount of addition, and when it is added in an amount exceeding 4 wt%, it is preferable to restrict the addition amount to 4 wt% .

Mn: 0.1 to 1 wt%

Manganese (Mn) is an element which decreases the iron loss by increasing the resistivity in addition to Si and Al, and plays a role of improving the texture. When too little Mn is added, the high-frequency iron loss effect is significantly reduced, and nitride and sulfide are formed finely to deteriorate magnetic properties. However, when it is added too much, the magnetic flux density is greatly reduced, so that the addition amount is limited to 0.1 to 1 wt%.

P: 0.01 to 0.1 wt%

Phosphorus (P) plays a role of lowering the iron loss by increasing the resistivity, and it plays a role of improving the texture by segregation at grain boundaries. However, if it is added excessively, it inhibits grain growth and lowers the cold rolling property, so it is added in the range of 0.01 to 0.1 wt%.

S: 0.001 to 0.005 wt%

Since sulfur (S) is an element which forms sulfides such as MnS, CuS and (Cu, Mn) S which are harmful to the magnetic properties, it is preferably added as low as possible. However, when it is added in an amount of less than 0.001% by weight, it is rather disadvantageous to the formation of aggregate structure and the magnetic property is deteriorated. If it is added in an amount of more than 0.005% by weight, the magnetism tends to be heated due to the increase of fine sulfides, so that it is contained in an amount of 0.001 to 0.005% by weight.

Al: 0.1 to 0.6 wt%

Aluminum (Al) is added because it increases the resistivity and reduces the iron loss, and also reduces the magnetic anisotropy and reduces the magnetization deviation in the rolling direction and in the direction perpendicular to the rolling direction. If the addition amount is too small, it is added in an amount of 0.1 wt% or more because it causes the magnetism to be swelled due to the fine AlN precipitates. When the addition amount is too large, the magnetic flux density is greatly reduced, so that the addition amount is limited to 0.1 to 0.6% by weight.

N: 0.005 wt% or less

Nitrogen (N) is an element harmful to magnetism such as nitrides formed by binding strongly with Al and Ti to inhibit crystal growth, and therefore it is preferable to contain N in an amount as small as 0.005 wt% or less.

Ti: 0.005 wt% or less

Titanium (Ti) forms fine carbides and nitrides to inhibit crystal growth. As the amount of titanium (Ti) increases, the texture is disadvantageously lowered due to increased carbides and nitrides, so that the magnetic properties are deteriorated.

Sn and Sb: 0.02 to 0.2 wt%

Tin (Sn) and antimony (Sb) are crystal grain segregated elements that inhibit the diffusion of nitrogen through grain boundaries and inhibit the formation of {111}, {112} The effect of adding them individually or in an amount of less than 0.02% by weight is insignificant. Addition of more than 0.2% by weight inhibits grain growth and decreases magnetism So that Sn and Sb are added individually or in an amount of 0.02 to 0.2% by weight in total.

Other impurities

In addition to the above-mentioned elements, inevitably incorporated impurities such as Cu, Ni, Cr, Zr, Mo and V may be included. Although these elements are trace amounts, they may cause magnetic deterioration through formation of intracellular inclusions. Therefore, Cu, Ni and Cr: 0.05 wt% or less and Zr, Mo and V: 0.01 wt% or less, respectively.

In addition to the above-mentioned composition, the remainder preferably contains Fe and unavoidable impurities, and the steel of the present invention does not exclude the addition of other compositions. The unavoidable impurities can not be intentionally mixed in the raw material or the surrounding environment in the ordinary steel manufacturing process, and can not be excluded. Such unavoidable impurities can be understood by those skilled in the ordinary steel manufacturing field.

The non-oriented electrical steel sheet according to one embodiment of the present invention should satisfy the following formulas 1 and 2 in addition to the above-mentioned composition ranges.

[Formula 1]

0.05? [P] + [Sn] + [Sb]? 0.15

[Formula 2]

0.5? [P] / ([Sn] + [Sb])? 2

P, Sn, and Sb are segregation elements in the grain boundaries, which are segregated at grain boundaries during recrystallization and have an effect of suppressing the formation of aggregate structure unfavorable to magnetism at grain boundaries. Therefore, it is important to effectively utilize P, Sn, and Sb. However, in the case of grain boundary segregation elements, since the grain growth is suppressed as the addition amount increases, it is difficult to obtain the desired crystal grains. Therefore, it is necessary to closely examine the relationship between magnetism and texture to control the addition amount.

Basically, P, Sn, and Sb are segregated at the grain boundaries during cold annealing after cold rolling at grain boundary segregation sources, thereby suppressing the formation of {111} and {112} texture structures unfavorable to magnetism, thereby improving the magnetism. However, increasing the amount of P, Sn, and Sb increases the grain growth inhibiting ability, so it is necessary to control the addition amount because grain size is made finer. In addition, when the addition amount of P and Sn / Sb is increased, it is not unconditionally good. However, when the amount of Sn and Sb is added, the adhesion and acidity are lowered to decrease the productivity The non-oriented electrical steel sheet excellent in magnetic properties and productivity at the same time can be produced.

In addition, the non-oriented electrical steel sheet according to one embodiment of the present invention should satisfy the following formula 3 in addition to the above-mentioned composition range.

[Formula 3]

(V _{111} + V _{112} ) / ([maximum intensity value]) * 100? 30

(Where V _{111} and V _{112} in Equation 3 are _{111} and _{112} in the texture analysis of the 3 / 4t portion of the plate thickness, in the orientation distribution function image (ODF image, }, And [the maximum intensity value] represents the maximum intensity value in the orientation distribution function image (ODF image, φ2 = 45 degree section).

The non-oriented electrical steel sheet according to an embodiment of the present invention has an average grain size of 30 to 150 탆. When the average grain size falls within the above range, a non-oriented electrical steel sheet excellent in magnetic properties and productivity can be obtained

The non-oriented electrical steel sheet according to one embodiment of the present invention is excellent in magnetic properties and particularly satisfies B1 / B50? 0.45. B1 and B50 represent magnetic flux density values induced in the steel sheet when a current of 100 A / m and 5000 A / m is applied, respectively.

[Formula 1]

0.05? [P] + [Sn] + [Sb]? 0.15

[Formula 2]

0.5? [P] / ([Sn] + [Sb])? 2

First, the slab is heated and hot-rolled to produce a hot-rolled sheet. The reason why the addition ratio of each composition is limited is the same as the reason for limiting the composition of the non-oriented electrical steel sheet described above. The composition of the slab is substantially unchanged in the course of the hot rolling, the annealing of the hot-rolled sheet, the cold rolling, and the annealing of the recrystallization to be described later, so that the composition of the slab and the composition of the non-oriented electrical steel sheet are substantially the same.

The slab is charged into a heating furnace and heated to 1100 to 1250 캜. If the heating temperature exceeds 1250 ° C, the precipitates such as AlN and MnS present in the slab may be re-heated at the time of hot rolling to inhibit grain growth and decrease magnetism, so that the reheating temperature is limited to 1100 to 1250 ° C.

The heated slab is hot-rolled to 2 to 2.3 mm to produce a hot-rolled sheet. Finishing rolling in hot rolling is finished in ferrite and final rolling reduction is performed at 10% or less for plate shape calibrating. Concretely, the finishing temperature in the step of producing the hot rolled sheet may be 800 to 1000 캜.

The produced hot rolled sheet may further include a step of winding at 500 to 750 ° C and cooling in air. The hot-rolled sheet subjected to coiling and cooling may be subjected to hot-rolled sheet annealing or may be omitted. When hot-rolled sheet annealing is performed, the annealing temperature is 900 to 1150 占 폚. If the annealing temperature of the hot-rolled sheet is lower than 900 캜, grain growth is insufficient and it is not easy to obtain aggregate structure favorable to magnetism during annealing after cold rolling, and when it exceeds 1150 캜, crystal grains excessively grow and surface defects The temperature of the hot-rolled sheet annealing is set to 900 to 1150 ° C.

The hot rolled sheet is pickled in a usual manner and then cold rolled. The cold rolling is finally rolled to a thickness of 0.10 mm to 0.70 mm. If necessary, it may be subjected to primary cold rolling and secondary annealing followed by secondary cold rolling, and the final reduction ratio is in the range of 50 to 95%.

The cold-rolled cold-rolled sheet is subjected to recrystallization annealing. In the step of recrystallization annealing the cold-rolled sheet, the cold-rolled sheet annealing can be carried out in a continuous annealing furnace.

In one embodiment of the present invention, the tension on the outgoing side of the annealing is 0.5 to 1.5 kg / mm ² , and the annealing temperature is 900 to 1100 캜. When the cold-rolled sheet is subjected to recrystallization annealing, if the tensile strength is too high, residual stress will remain to dislodge magnetism, while if it is too low, the productivity will deteriorate due to plate shape, defects, and the like. If the cold-rolled sheet recrystallization annealing temperature is less than 900 ° C, the growth of the crystal grains is insufficient and the {111} texture, which is harmful to the magnetism, increases. When the annealing temperature exceeds 1100 ° C, the crystal grains grow excessively, The recrystallization annealing temperature of the plate is 900 to 1100 캜.

The recrystallized annealed sheet is treated with insulation coating and shipped to the customer. The insulating coating can be treated with an organic, inorganic or organic composite coating, and other insulating coatings can be used. The customer can use this steel sheet as it is and can use it after stress relieving annealing if necessary.

Hereinafter, the present invention will be described in more detail with reference to examples. However, these embodiments are only for illustrating the present invention, and the present invention is not limited thereto.

Example One

The slabs formed as shown in Table 1 below were heated at 1200 DEG C, hot rolled to a thickness of 2.8 mm, and then wound. The hot-rolled steel sheet obtained by winding and cooling in air was annealed at 1030 캜 for hot-rolled sheet, pickled, cold-rolled to a thickness of 0.50 mm, and annealed at 1000 캜 for 80 seconds. At this time, the tension on the exit side of the annealing furnace during annealing of the cold rolled steel sheet was controlled so as to satisfy 1.0 kg / mm ² . For each specimen, the surface of the specimen parallel to the rolling direction was polished to a thickness of 3 / 4t, and then EBSD and X-ray diffractometer were used to measure the (110), (200) and (211) The volume fraction V _{111} , V _{112} and max intensity of {111}, {112} texture were measured. In addition, a magnetic loss (W / kg) of an iron loss (W15 / 50) and a magnetic field of 100 A / m and 5000 A / m in the rolling direction and the perpendicular direction in the rolling direction when magnetic flux density of 1.5 Tesla was induced at 50 Hz frequency was added The magnetic flux density (B1, B50), which is the magnitude of the magnetic flux density (Tesla), is measured. The results are shown in Table 2 below.

Steel grade C Si Mn P S Al N Ti Sn Sb A1 0.0018 1.9 0.76 0.05 0.0011 0.31 0.0035 0.0024 0.05 0.02 A2 0.003 1.2 0.12 0.089 0.0041 0.3 0.0018 0.0014 0 0.05 A3 0.003 3.1 0.85 0.014 0.0028 0.64 0.0028 0.004 0.02 0.01 A4 0.0046 2.2 0.14 0.074 0.0035 0.38 0.0037 0.0023 0.06 0.07 A5 0.0028 2.8 0.51 0.027 0.0048 0.53 0.0006 0.0043 0.01 0.04 A6 0.0042 2.1 0.62 0.067 0.0013 0.23 0.0011 0.0018 0 0.04 A7 0.0041 1.1 0.58 0.083 0.0035 0.4 0.0016 0.0026 0.03 0.01 A8 0.0014 3.5 1.04 0.035 0.0022 0.48 0.0024 0.0019 0.02 0.07 A9 0.0019 3 0.57 0.032 0.0018 0.21 0.0032 0.001 0.05 0 A10 0.0034 3.3 0.51 0.046 0.0029 0.34 0.0027 0.0036 0.06 0.02

Steel grade Equation 1 Value Equation 2 Value Equation 3 Value B1 / B50 Iron loss W15 / 50 Magnetic flux density
B50 Remarks A1 0.120 0.71 16 0.48 3.31 1.75 Honor A2 0.139 1.78 29 0.51 3.86 1.75 Honor A3 0.044 0.47 9 0.48 4.25 1.68 Comparative Example A4 0.204 0.57 11 0.46 4.42 1.69 Comparative Example A5 0.077 0.54 25 0.52 2.41 1.73 Honor A6 0.107 1.68 17 0.51 2.74 1.74 Honor A7 0.123 2.08 8 0.49 4.68 1.7 Comparative Example A8 0.125 0.39 11 0.47 4.15 1.68 Comparative Example A9 0.082 0.64 18 0.55 2.32 1.72 Honor A10 0.126 0.58 23 0.53 2.19 1.72 Honor

As shown in Table 1 and Table 2, A1, A2, A5, A6, A9 and A10 satisfying the composition of the present invention, the formulas 1 to 3 and the average grain size are excellent in the iron loss W15 / 50 and the magnetic flux density B50 appear.

On the other hand, A3 did not satisfy the control range of Al content and did not satisfy all of Equations 1 to 3. As a result, iron loss and magnetic flux density were inferior.

A4 satisfied the composition range but did not satisfy Equation 1. As a result, iron loss and magnetic flux density were inferior.

A7 satisfied the composition range, but did not satisfy the equations (2) and (3). As a result, iron loss and magnetic flux density were inferior.

A8 of the present invention satisfies the composition formula of 0.05? [P] + [Sn] + [Sb]? 0.15, while [Al], [P], [Sn], and [Sb] ] Did not satisfy the control range and the composition formula of 0.5 ≤ [P] / ([Sn] + [Sb]) ≤2 was also unsatisfactory. As a result, iron loss and magnetic flux density were inferior.

Example 2

The slabs prepared as shown in Table 3 were heated at 1220 占 폚, hot rolled to a thickness of 2.4 mm, and then wound. The hot-rolled steel sheet taken up in the air was annealed at a temperature of 1050 캜 for annealing, pickled, cold-rolled to a thickness of 0.50 mm, and cold rolled sheet annealing was carried out. Annealing temperature and furnace tension were changed as shown in Table 4 Followed by final recrystallization annealing. The grain size was measured by EBSD and X-ray pole figure test, grain size was measured by intercept method, and iron loss (W15 / 50) and magnetic flux density (B1, B50) The results are shown in Table 4 below.

Steel grade C Si Mn P S Al N Ti Sn Sb B1 0.0036 2.7 0.48 0.037 0.0036 0.21 0.0014 0.0032 0 0.04 B2 0.0016 1.8 0.64 0.044 0.0033 0.28 0.0029 0.0021 0.03 0 B3 0.003 3.4 0.52 0.031 0.0034 0.3 0.0015 0.0016 0.04 0.02 B4 0.0023 1.8 0.75 0.016 0.0044 0.45 0.002 0.0026 0.07 0.03 B5 0.004 2.3 0.38 0.052 0.0023 0.2 0.0028 0.0012 0.03 0.04 B6 0.0039 3 0.23 0.035 0.002 0.4 0.0011 0.0043 0.06 0 B7 0.0017 2.4 0.3 0.113 0.0015 0.22 0.0026 0.003 0.03 0.01 B8 0.001 2.2 0.19 0.068 0.0021 0.43 0.0033 0.0028 0 0.04 B9 0.0029 1.6 0.4 0.012 0.0016 0.34 0.0025 0.0022 0 0.03 B10 0.0021 3.1 0.34 0.036 0.0022 0.3 0.0015 0.0023 0.05 0 B11 0.0041 2.7 0.71 0.045 0.0033 0.38 0.0016 0.0018 0.06 0.01 B12 0.0029 2.6 0.47 0.033 0.0021 0.17 0.0024 0.0014 0.02 0.07

Steel grade Equation 1 Value Equation 2 Value Equation 3 Value Average grain
Particle size
(탆) Recrystallization annealing temperature (캜) tension
(kg / mm ² ) B1 / B50 Iron loss W15 / 50 Magnetic flux density
B50 Remarks B1 0.077 0.93 24 82 960 1.2 0.56 2.45 1.73 Honor B2 0.074 1.47 16 126 1060 0.7 0.49 2.67 1.76 Honor B3 0.091 0.52 18 102 1010 1.0 0.45 2.32 1.72 Honor B4 0.116 0.16 17 160 1120 1.2 0.51 4.26 1.68 Comparative Example B5 0.122 0.74 15 131 1030 1.3 0.46 2.84 1.75 Honor B6 0.095 0.58 12 25 850 1.1 0.47 4.11 1.66 Comparative Example B7 0.153 2.83 11 67 940 1.7 0.42 4.36 1.67 Comparative Example B8 0.108 1.70 22 86 1020 1.2 0.5 2.68 1.75 Honor B9 0.042 0.40 9 125 1080 1.6 0.44 4.55 1.69 Comparative Example B10 0.086 0.72 13 113 980 1.3 0.48 2.33 1.73 Honor B11 0.115 0.64 17 95 990 0.6 0.56 2.52 1.74 Honor B12 0.123 0.37 8 28 880 1.7 0.39 4.23 1.67 Comparative Example

As shown in Table 4, B1, B2, B3, B5, B8, B10 and B11 satisfying the composition of the slab of the present invention, the formula 1 and the formula 2, the tension and the temperature of the annealing furnace during the annealing of the recrystallization, An electrical steel sheet having a grain size satisfying a specific range was produced. As a result, the iron loss W15 / 50 and the magnetic flux density B50 were excellent.

In B4, the value of the formula 2 and annealing temperature of the recrystallization were out of the range, and the average grain size was out of order. As a result, iron loss and magnetic flux density were inferior.

B6 is too low in annealing temperature for recrystallization, and grain size is fine, resulting in poor iron loss and magnetic flux density.

In B7, the addition amount of P did not satisfy the composition range, and the annealing furnace tension was too high to satisfy the condition, and iron loss and magnetic flux density were inferior.

B9 did not satisfy Eq. 1 and Eq. 2, and the annealing furnace tension was too high to satisfy the condition, so the value of Eq. 3 did not satisfy the specified range. As a result, iron loss and magnetic flux density were inferior.

B12 did not satisfy Eq. 2, and annealing temperature was too low for annealing of cold rolled steel sheet, so the grain size was too small to satisfy the condition, and the value of Eq. 3 did not satisfy the specified range because it did not satisfy the tension condition. As a result, iron loss and magnetic flux density were inferior.

It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. It will be understood that the invention may be practiced. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims

0.001 to 0.005% of C, 0.1 to 0.6% of Al, 0.1 to 1% of Cr, 0.1 to 1% of Mn, 0.01 to 0.1% of P, 0.005% or less (excluding 0%) of N, 0.005% or less (excluding 0%) of Ti, 0.02 to 0.2% of Sn and Sb alone or in an amount of 0.005% or less An unoriented electric steel sheet which contains unavoidable impurities and satisfies the following formulas 1 to 3 and has an average grain size of 30 to 150 占 퐉.
[Formula 1]
0.05? [P] + [Sn] + [Sb]? 0.15
[Formula 2]
0.5? [P] / ([Sn] + [Sb])? 2
[Formula 3]
(V _{111} + V _{112} ) / ([maximum intensity value]) * 100? 30
(P, Sn and Sb in the formulas 1 to 3 represent the content (% by weight) of P, Sn and Sb, respectively,
V _{111} and V _{112} are the texture fractions of {111} and {112} in the azimuth distribution function image (ODF image, φ2 = 45 degree section) , And [Maximum intensity value] represents the maximum intensity value in the orientation distribution function image (ODF image, φ2 = 45 degree section).

The method according to claim 1,
B1 / B50 ≥ 0.45 non-oriented electrical steel.
(B1 and B50 represent the value of the magnetic flux density induced in the steel sheet when a current of 100 A / m and 5000 A / m is applied, respectively).

The method according to claim 1,
Further comprising 0.05% by weight or less (excluding 0% by weight) of Cu, Ni and Cr, respectively.

The method according to claim 1,
Zr, Mo, and V in an amount of 0.01 wt% or less (excluding 0 wt%), respectively.

0.001 to 0.005% of C, 0.1 to 0.6% of Al, 0.1 to 1% of Cr, 0.1 to 1% of Mn, 0.01 to 0.1% of P, 0.005% or less (excluding 0%) of N, 0.005% or less (excluding 0%) of Ti, 0.02 to 0.2% of Sn and Sb alone or in an amount of 0.005% or less A step of producing a hot rolled sheet by heating a slab containing unavoidable impurities and satisfying the following formulas 1 and 2 and then hot rolling;
Cold-rolling the hot-rolled sheet to produce a cold-rolled sheet; And
And recrystallizing and annealing the cold-rolled sheet at 900 to 1100 占 폚,
Wherein a tensile force on the outgoing side of the annealing furnace in the step of recrystallization annealing is 0.5 to 1.5 kg / mm ² , and the produced steel sheet satisfies the following formula (3).
[Formula 1]
0.05? [P] + [Sn] + [Sb]? 0.15
[Formula 2]
0.5? [P] / ([Sn] + [Sb])? 2
(Where P, Sn and Sb in the formulas 1 and 2 represent the contents (% by weight) of P, Sn and Sb, respectively).
(V _{111} + V _{112} ) / ([maximum intensity value]) * 100? 30
(Where V _{111} and V _{112} in Equation 3 are _{111} and _{{111} in the} texture analysis of the 3 / 4t portion of the plate thickness, 112}, and [maximum intensity value] represents the maximum intensity value in the orientation distribution function image (ODF image, φ2 = 45 degree section).

6. The method of claim 5,
Wherein the slab is heated to 1100 to 1250 占 폚 in the step of producing the hot-rolled steel sheet.

6. The method of claim 5,
Further comprising a step of winding the hot-rolled sheet at 500 to 750 占 폚 after the step of producing the hot-rolled sheet.

8. The method of claim 7,
Further comprising the step of annealing the hot-rolled steel sheet at 900 to 1150 占 폚 after the winding step.

6. The method of claim 5,
The method of producing a non-oriented electrical steel sheet according to any one of the preceding claims, wherein in the step of producing the cold-rolled sheet, the reduction ratio is 50 to 95%.

delete

6. The method of claim 5,
Wherein the produced steel sheet has a blast ratio of B1 / B50 ≥ 0.45.
(B1 and B50 represent the value of the magnetic flux density induced in the steel sheet when a current of 100 A / m and 5000 A / m is applied, respectively).

6. The method of claim 5,
Wherein the produced steel sheet has an average grain size of 30 to 150 占 퐉.

6. The method of claim 5,
Wherein the slab further comprises 0.05 wt% or less (excluding 0 wt%) of Cu, Ni and Cr, respectively.

6. The method of claim 5,
Wherein the slab further comprises Zr, Mo and V in an amount of 0.01 wt% or less (excluding 0 wt%), respectively.